System and method for management of a DC and AC bus microgrid

ABSTRACT

Systems and methods are described herein for managing the operations of a microgrid module. The microgrid module includes transformers and/or power converters necessary for modifying the input AC or DC power sources to meet the required characteristics of the output power. The microgrid module further comprises a power management software module and a control software module installed on a microgrid computer. The power management software module receives business parameters such as prices from power contracts. The power management software module uses the parameters to create rules for applying to the operation of the microgrid module. The rules the power management software module creates are stored locally at the microgrid computer so that they can be quickly accessed by a control software module. The control software module uses the rules in combination with data collected from sensors installed in the physical circuitry layer of the microgrid module to control the operations of the microgrid module.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application incorporates by reference in their entirety thefollowing co-owned United States patent applications: System and Methodfor Routing Power Across Multiple Microgrids Having DC and AC Buses,having Ser. No. 12/760,631, and System and Method for a ControlledInterconnected DC and AC Bus Microgrid, having Ser. No. 12/760,647, bothof which are being filed concurrently with this application.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to microgrids for controllingsmall distributed energy resources (DERs). More specifically, thepresent invention relates to a system and method for using businessparameters to manage the operations of a microgrid with DC and AC inputsand outputs.

2. Description of Related Art

In general, microgrids are electric networks that are capable ofderiving power from a number of sources including the conventional powergrid, localized power generating capabilities and alternative powersources such as solar arrays and wind turbines. The microgrid canaggregate power from a number of sources, converting the differentformats of power derived from multiple and diverse sources to commonvoltage and frequency formats that can be subsequently distributed toone or a number of loads. In addition, the microgrid can maintain thereliability of power to one or a number of loads in the face of changingpower levels that are derived from the multiple and diverse sources. Amicrogrid can be coordinated to provide power from a variety of powersources and to provide power with greater reliability. For example, amicrogrid can provide an alternate source of power to a site when thereis an interruption in the power delivered by the conventional utilitypower grid. A microgrid also can provide an alternate source of power,such as power from a renewable energy source, when renewable energy ispreferred over power delivered by the conventional utility power grid.The power that the microgrid supplies to a site may be derived from avariety of sources including energy storage devices, alternative energysources such wind or solar power, or from burning conventional fossilfuels. A description of prior art microgrid configurations is found inthe whitepaper entitled “Characterization of Microgrids in the UnitedStates” prepared for Sandia National Laboratories by Resource DynamicsCorporation dated January 2005 and incorporated herein by reference inits entirety.

In general, there are prior patents and published patent applicationsdirected to various aspects of microgrids. For example, U.S. Pat. No.6,819,087 discloses a distributed resource stabilization control formicrogrid applications. U.S. Pat. No. 6,778,414 relates to a distributedsystem and methodology for electrical power regulation, conditioning anddistribution on an aircraft. U.S. Pat. No. 6,765,370 discloses a systemand method for bi-directional power conversion in a portable device.U.S. Published Patent Application No. 2008/0143304 describes a systemand method for controlling a microgrid.

The disclosures in these prior patents and published patent applicationsis hereby incorporated herein by reference in their entirety. However,as described further below, none of these prior patents or publishedpatent applications provides the solutions of the invention describedand claimed in this application.

SUMMARY OF THE INVENTION Summary of the Problem

The present state of the art for microgrid technology has severaldeficiencies, including the absence of a comprehensive system and methodfor managing the operation of a microgrid module capable of handling ACto AC, DC to DC, AC to DC, and DC to AC across multiple inputs andoutputs. There is a further need to be able to use business rulesderived, for example, from power pricing contracts and load sharingagreements, to manage the operation of the microgrid module. Also absentfrom the prior art is a scalable system capable of managing multiplemicrogrid modules. Finally, there is a need for a microgrid module powermanagement system that can receive feedback from the operation of themicrogrid module and adjust operating rules based on that feedback.

Thus there is a need for advances in the art of electrical microgridsand their management that addresses these deficiencies. Suchdeficiencies are overcome by the present invention, as is furtherdetailed below.

Summary of the Solution

The present invention addresses the foregoing limitations in theexisting art by providing a system and method for managing a microgridthat can operate with AC to AC, DC to DC, AC to DC, and DC to AC acrossmultiple inputs and outputs. The present invention comprises a powermanagement software module installed in a computing device coupled to amicrogrid module. The power management software module can operate as adistributed control point capable of managing one or more microgridmodules. The power management software module can use parameters fromcontracts and business operations to establish rules for the operationof a microgrid module. In conjunction with a control software module,the power management software module can communicate with softwareoperating sensors and controllable elements in the physical circuitrylayer to manage the flow of power to and from the microgrid module.

In a first exemplary embodiment, the invention comprises an apparatusfor managing a microgrid module comprising a microgrid computer coupledto the circuit layer of the microgrid module. The microgrid computer cancomprise a power management software module that processes a businessparameter such as a price associated with a power contract and creates arule from the business parameter. The rule is stored in acomputer-readable storage device for access by a control software moduleinstalled on the microgrid computer. The control software module is incommunication with software at the physical circuit layer of themicrogrid module. The software at the physical circuit layer operatessensors and controllable elements installed among the components of thephysical circuit layer. The control software module can receive datafrom a sensor in the physical circuit layer, for example, dataindicating an interruption in AC power supplied to the microgrid module.The control software module can apply the rule created by the powermanagement module to the data received from the sensor in order toselect a command to alter the operation of the microgrid module. Thecontrol software module can send the command to a controllable element,for example, a controllable element that initiates power delivery froman alternate power source to the microgrid module.

In another exemplary embodiment, the invention comprises a method formanaging a microgrid module. The exemplary method begins with amicrogrid computer storing a business parameter for access by a powermanagement software module. The power management software module canconvert the business parameter to a rule which is stored in memory withthe microgrid computer. A control software module can access the ruleand, in combination with data received from a sensor in the circuitlayer of the microgrid module, the control software layer can select acommand for altering the operation of the microgrid module. The controlsoftware layer can transmit the command to a controllable element in thecircuit layer. For example, the command may initiate the delivery ofpower to the microgrid module from an alternate power source.

In yet another exemplary embodiment, the invention comprises acomputer-readable medium comprising computer-executable instructions forexecution on a microgrid computer. The computer-executable instructionsinclude instructions for a power management software module to access astored business parameter and to convert the business parameter to arule for use by a control software module. The computer-executableinstructions also include instructions for the control software moduleto receive data from a sensor in the circuit layer of the microgridmodule and to use the received data in combination with the stored ruleto select a command for altering the operation of the microgrid module.The computer-executable instructions further include instructions forthe control software module to transmit the command to a controllableelement in the circuit layer to initiate the delivery of power to themicrogrid module from an alternate power source.

These and other exemplary embodiments of the invention will be describedin greater detail in the following text and in the associated figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram illustrating an overview of components in accordancewith an exemplary embodiment of the invention.

FIG. 2 is a diagram illustrating an overview of components in accordancewith an exemplary embodiment of the invention.

FIG. 2A is a diagram illustrating the components of a computing devicein accordance with an exemplary embodiment of the invention.

FIG. 3 is a diagram illustrating an overview of the components of thephysical circuit layer in accordance with an exemplary embodiment of thepresent invention.

FIGS. 4A through 4D are diagrams illustrating portions of the componentsof the physical circuit layer in accordance with an exemplary embodimentof the present invention.

FIG. 5 is a diagram illustrating components of a microgrid in accordancewith an exemplary embodiment of the invention.

FIG. 6 is a diagram illustrating components of a mobile microgrid inaccordance with another exemplary embodiment of the invention.

FIG. 7 is a flow chart diagram illustrating a process in accordance withan exemplary embodiment of the present invention.

DETAILED DESCRIPTION

The present invention comprises a portable microgrid module that isfully integrated and can manage both AC and DC inputs and AC and DCoutputs. The microgrid module includes a computer comprising softwarefor managing the operations of the microgrid module and a circuit layercomprising AC and DC buses, sensors, controllable elements, andconverters. The computer further comprises a control software module, apower management module, and memory for storing rules associated withthe operation of the microgrid module. The microgrid module also caninclude or be coupled to energy storage devices such as batteries andcapacitors. As described in further detail in related patentapplications filed herewith, the microgrid module also has thecapability of being coupled to one or more other microgrid modules. Theintegrated control of the connection of multiple DC and AC buses withinthe microgrid module allows for deterministic real-time control overbi-directional power sources from intermittent and continuous renewableand conventional power sources. Real-time control over the distributedpower sources supplying the microgrid module allows the microgrid moduleto respond to interruptions in one power supply and to transition toanother power supply.

The microgrid module of the present invention can accept alternative,renewable, and conventional power inputs into both DC and AC buses anddistributes or converts them as appropriate to match standardized busvalues across the input, load, macrogrid, and microgrid to microgridbuses. The microgrid module can provide power conversion from DC to DC,AC to AC, AC to DC and DC to AC between the buses under dynamic localcontrol. The microgrid of the present invention also has the capacity tostore electrical energy or energy in a form transmutable into electricalenergy, such as in a chemical form, for later distribution.

Each microgrid module can comprise various sub-systems and devices thatinclude, but are not limited to, quick-connect/quick-disconnect bus barsand plates, step-up and step-down transformers, patch orinter-connection panels and intelligent breakers and sensors, batteries,ultra-capacitors, flywheels, and other temporary or permanent energystorage devices and systems and their control electronics. The microgridmodule can also include power converters, circuitry to accommodate phaseimbalance by providing the appropriate neutral connections, and variousphysical wiring and physical mounting capabilities to provide foradequate stabilization and insulation of the various components in themodular microgrid system.

As referenced above, installed on the microgrid module's computer are apower management software module and a control software module. Thepower management software module can retrieve one or more businessparameters stored in a computer-readable memory and convert the one ormore business parameters to rules for operating the microgrid module.The power management software module can store the rules in a localcomputer-readable memory typically located in the microgrid module'scomputer. The control software module receives data from sensors locatedin the physical circuitry layer of the microgrid module. The controlsoftware module can apply the rules stored in the localcomputer-readable memory to the data received from the sensors todetermine which commands to send to the physical circuitry layer. Thecontrol software module sends commands to controllable elements locatedin the physical circuitry layer to control the operation of themicrogrid module.

Turning to the figures, in which like numerals indicate like elementsthroughout the figures, exemplary embodiments of the present inventionare illustrated and will be described in the following text. Those ofskill in the art will appreciate that the following are merelynon-limiting preferred embodiments and alternate embodiments can beimplemented in accordance with the invention.

Referring to FIG. 1, an exemplary architecture for a microgrid module 5can be depicted in three layers. The first layer is the physicalcircuitry layer 10. The physical circuitry layer comprises the AC and DCinput and output buses, the sensors and controllable elements thatmonitor and control the flow of power into and out of the microgridmodule, and other conventional electrical components such as convertersand transformers. The sensors and controllable elements that monitor andcontrol the microgrid module can vary from simple sensors and switchesto more complex “intelligent” sensors and switches that can includetheir own software and processing capabilities. Exemplary, non-limitingembodiments of the physical circuitry layer 10 are depicted in greaterdetail in FIG. 3, FIGS. 4A-4D and in the related application entitled“System and Method for a Controlled Integrated DC and AC Bus Microgrid”filed concurrently with this application.

The intermediate layer of the architecture for the microgrid is thecontrol software layer 15 and the final layer is the rules managementlayer 20 which includes business, regulatory and safety rules. Thecontrol software layer 15 is typically installed on a local computingdevice and can be implemented in, for example, active messagequeuing/message broker software as is known to those of ordinary skillin the art. While the control software layer is typically installed on alocal computing device that is part of the microgrid module, those ofordinary skill in the field will understand that software modulescontrolling the microgrid module or its components can be installed incomponents of the physical circuit layer or in other computing devicescoupled to the microgrid module. The rules management layer 20 also istypically installed on a local computing device and can be implementedin, for example, a virtual machine with a service oriented architectureand use SOAP (Simple Object Access Protocol) as a messaging protocol.The rules management layer 20 comprises the power management softwaremodule referenced above and described in greater detail in the followingtext.

Referring to FIG. 2, another exemplary architecture diagram illustratesin further detail the components of an exemplary microgrid module. FIG.2 shows the physical circuit layer 205 comprising sensors 210 andcontrollable elements 215. The sensors 210 can collect data from the ACand DC buses (not shown in FIG. 2) and deliver the collected data to themicrogrid computer 220. The sensors 210 can detect a variety of powerconditions including direction, voltage, current and power levels, andassociated changes and the rate of change of these parameters. Forexample, the sensors can provide data indicating a demand for power,data indicating the flow of power within the microgrid module, and dataindicating an interruption in the flow of power to the microgrid module.The controllable elements 215 can include switches, power converters,and other intelligent electrical devices to control the flow of power toand from the microgrid module. Intelligent electrical devices typicallyinclude their own software and processing capabilities. The controllableelements 215 can receive commands from the control software module 225of the microgrid computer 220. In certain embodiments, intelligentcontrollable elements can perform control functions withoutcommunicating with a separate microgrid computer.

The microgrid computer 220 provides a single or multiple user interfaceto the various controllable microgrid elements. The microgrid computer220 communicates with the sensors 210 and controllable elements 215 ofthe physical circuit layer. The microgrid computer 220 comprisesinstalled power management software module 228 and control softwaremodule 225. The power management software module 228 can retrievebusiness parameters from computer memory such as remote memory device238. The power management software module converts the businessparameters into rules that the control software module 225 can apply tothe operation of a microgrid module. The control software module 225uses the rules to process data received from the sensors 210 andgenerate commands for sending to the controllable elements 215. Themicrogrid computer 220 can also comprise power router software module230 that controls the flow of power to and from the microgrid module andother microgrid modules. For example, in certain embodiments multiplemicrogrid modules can be coupled in various arrangements.

The microgrid computer 220 also can comprise local data storage 235 andcan be coupled to remote data storage 238. The remote storage device 238can store business parameters, sensor data, and log data. The businessparameters can be defined by the operator of the microgrid and mayrepresent a variety of “real world” parameters. As one example, thebusiness parameters can represent the costs of power from theconventional AC power grid and from alternate power sources coupled tothe microgrid. In another example, the business parameters can representexpected load demands and preferences for certain power sources. Thesensor data that can be stored at the remote data storage device 238 isthe data the control software module 225 receives from the sensors 210.The power management software module 228 can access this sensor data toadjust the rules based on the operation of the microgrid module. Theremote storage device 238 can also store log data describing theoperation of the microgrid module over time that can be used for furtherplanning and operation of the microgrid module.

In the preferred embodiment, the local data storage 235 stores the rulescreated by the power management software module 228 from the businessparameters. The control software module 225 uses the rules to controlthe controllable elements 215. Locally storing the rules assists thecontrol software module 225 to respond quickly to changes in powersupplied to the microgrid module. For example, the rules can define whenthe microgrid module will draw power from a power storage device or fromthe conventional utility grid. More generally, the rules can controlvarious operating modes for the microgrid module including islanding,peak shaving, power conditioning, aggregate load reduction, and the saleof power back to a utility. In alternate embodiments of the invention,software modules and data storage devices can be located either locallyor remotely in different arrangements of computing environments.

Although the exemplary embodiments herein are generally described in thecontext of software modules running on a computing device local to thephysical circuitry layer as in FIG. 2, those skilled in the art willrecognize that the present invention also can be implemented inconjunction with other program modules in other types of computingenvironments. Furthermore, those skilled in the art will recognize thatthe present invention may be implemented in a stand-alone or in adistributed computing environment. In a distributed computingenvironment, program modules may be physically located in differentlocal and remote memory storage devices. Execution of the programmodules may occur locally in a stand-alone manner or remotely in aclient/server manner. Examples of such distributed computingenvironments include local area networks of an office, enterprise-widecomputer networks, and the global Internet.

The detailed description of the exemplary embodiments includes processesand symbolic representations of operations by conventional computercomponents, including processing units, memory storage devices, displaydevices and input devices. These processes and symbolic representationsare the means used by those skilled in the art of computer programmingand computer construction to most effectively convey teachings anddiscoveries to others skilled in the art. These processes and operationsmay utilize conventional computer components in a distributed computingenvironment, including remote file servers, remote computer servers, andremote memory storage devices. Each of these conventional distributedcomputing components is accessible by a processing unit via acommunications network.

The present invention includes computer hardware and software whichembody the functions described herein and illustrated in the appendedflow charts. However, it should be apparent that there could be manydifferent ways of implementing the invention in computer programming,and the invention should not be construed as limited to any one set ofcomputer program instructions. Further, a skilled programmer would beable to write such a computer program to implement the disclosedinvention without difficulty based on the flow charts and associateddescription in the application text, for example. Therefore, disclosureof a particular set of program code instructions is not considerednecessary for an adequate understanding of how to make and use theinvention. The inventive functionality of the claimed computer hardwareand software will be explained in more detail in the followingdescription in conjunction with the other figures in the application.

Referring now to FIG. 2A, aspects of an exemplary computing environmentin which the present invention can operate are illustrated. Thoseskilled in the art will appreciate that FIG. 2A and the associateddiscussion are intended to provide a brief, general description of thepreferred computer hardware and program modules, and that additionalinformation is readily available in the appropriate programming manuals,user's guides, and similar publications.

FIG. 2A illustrates a conventional computing device 120 suitable forsupporting the operation of the preferred embodiment of the presentinvention such as the microgrid computer. As illustrated previously inFIG. 2, the microgrid computer 220 typically comprises multiple softwaremodules. While not required for the computing device implemented in amicrogrid module, the computing device 120 illustrated in FIG. 2Aoperates in a networked environment with logical connections to one ormore remote computers 111. The logical connections between computingdevice 120 and remote computer 111 are represented by a local areanetwork 173 and a wide area network 152. Those of ordinary skill in theart will recognize that in this client/server configuration, the remotecomputer 111 may function as a file server or computer server.

The computing device 120 includes a processing unit 121, such as“PENTIUM” microprocessors manufactured by Intel Corporation of SantaClara, Calif. The computing device 120 also includes system memory 122,including read only memory (ROM) 124 and random access memory (RAM) 125,which is connected to the processor 121 by a system bus 123. Thepreferred computing device 120 utilizes a BIOS 126, which is stored inROM 124. Those skilled in the art will recognize that the BIOS 126 is aset of basic routines that helps to transfer information betweenelements within the computing device 120. Those skilled in the art willalso appreciate that the present invention may be implemented oncomputers having other architectures, such as computers that do not usea BIOS, and those that utilize other microprocessors.

Within the computing device 120, a local hard disk drive 127 isconnected to the system bus 123 via a hard disk drive interface 132. Afloppy disk drive 128, which is used to read or write a floppy disk 129,is connected to the system bus 123 via a floppy disk drive interface133. A CD-ROM or DVD drive 130, which is used to read a CD-ROM or DVDdisk 131, is connected to the system bus 123 via a CD-ROM or DVDinterface 134. A user enters commands and information into the computingdevice 120 by using input devices, such as a keyboard 140 and/orpointing device, such as a mouse 142, which are connected to the systembus 123 via a serial port interface 146. Other types of pointing devices(not shown in FIG. 2A) include track pads, track balls, pens, headtrackers, data gloves and other devices suitable for positioning acursor on a computer monitor 147. The monitor 147 or other kind ofdisplay device is connected to the system bus 123 via a video adapter148.

The remote computer 111 in this networked environment is connected to aremote memory storage device 150. This remote memory storage device 150is typically a large capacity device such as a hard disk drive, CD-ROMor DVD drive, magneto-optical drive or the like. Those skilled in theart will understand that software modules are provided to the remotecomputer 111 via computer-readable media. The computing device 120 isconnected to the remote computer by a network interface 153, which isused to communicate over the local area network 173.

In an alternative embodiment, the computing device 120 is also connectedto the remote computer 111 by a modem 154, which is used to communicateover the wide area network 152, such as the Internet. The modem 154 isconnected to the system bus 123 via the serial port interface 146. Themodem 154 also can be connected to the public switched telephone network(PSTN) or community antenna television (CATV) network. Althoughillustrated in FIG. 2A as external to the computing device 120, those ofordinary skill in the art can recognize that the modem 154 may also beinternal to the computing device 120, thus communicating directly viathe system bus 123. Connection to the remote computer 111 via both thelocal area network 173 and the wide area network 152 is not required,but merely illustrates alternative methods of providing a communicationpath between the computing device 120 and the remote computer 111.

Although other internal components of the computing device 120 are notshown, those of ordinary skill in the art will appreciate that suchcomponents and the interconnection between them are well known.Accordingly, additional details concerning the internal construction ofthe computing device 120 need not be disclosed in connection with thepresent invention.

Those skilled in the art will understand that program modules, such asan operating system 135 and other software modules 160 a, 163 a and 166a, and data are provided to the computing device 120 viacomputer-readable media. In the preferred computing device, thecomputer-readable media include the local or remote memory storagedevices, which may include the local hard disk drive 132, floppy disk129, CD-ROM or DVD 131, RAM 125, ROM 124, and the remote memory storagedevice 150.

Referring to FIG. 3, an exemplary microgrid module 300 is shown. Asillustrated, the microgrid module 300 may operate from a variety ofpower sources, including a connection to the local utility grid 320 andone or more distributed energy resources (“DERs”) 310 such as internalcombustion engine/generator sets, microturbine generators, fuel cells,wind turbines, and photovoltaic arrays. In addition, the microgridnetwork may have to level the power demands of various loads against theavailable power sources using energy storage assets 330 which mayinclude batteries (as shown), flywheels, electrochemical capacitorsand/or superconducting magnetic energy storage components (SMES).

Although the microgrid module 300 is labeled as a 250 kVA module, thatvalue is merely an example and other microgrid modules within the scopeof this invention can be designed to handle smaller or larger amounts ofpower. The microgrid module may have to provide power to several loadsystems with a variety of power format requirements including 208 V-3phase, 480 V-3 phase, 120 V-single phase, 48 VDC, and 300 VDC asexamples. As illustrated in FIG. 3, the microgrid module 300 includesone or more AC output buses that supplies power to one or more AC loads340. Exemplary microgrid module 300 also includes a DC output bus 350supplying power to a DC load. Processing power to flow from varioussources to various load and energy storage assets and from energystorage assets to the loads requires the use of power conversion tointerface various incoming and outgoing power formats.

The exemplary embodiments set forth in FIGS. 4A-4D illustrate in greaterdetail the components of the microgrid module 300 shown in FIG. 3. FIGS.4A-4D are broken up into four more detailed components of the overviewshown in FIG. 3. Those of skill in the art will recognize that theembodiments shown in FIGS. 4A-4D may be modified by adding, removing, orrearranging conventional electrical components without departing fromthe scope of the invention.

Turning to FIG. 4A, DERs 310 are illustrated as connected to DC inputbus 420. As illustrated in FIG. 4A, the microgrid module may compriseone or more DC input buses 420 and may be coupled to one or more DERs310. As explained previously, the DERs 310 can be one or more of avariety of energy sources, including conventional and renewable energysources. If the DER 310 is an AC power source, a converter 415 can beused to convert the AC power to DC power for transmission onto the DCinput bus 420. The DC input bus 420 can also be coupled to a DCdiagnostic element 417. The DC diagnostic element 417 can comprise oneor more sensors that can communicate with the control software module225.

FIG. 4A also illustrates an exemplary AC grid connection 320 thatconnects to the AC grid input bus 409 of the microgrid module. Theconnection with the AC grid allows power from the conventional utilitygrid to be fed to the microgrid module. In certain embodiments atransformer 405 will be necessary to adjust the voltage of the powerflowing from the utility grid to the microgrid module. An AC diagnosticmodule 407 can also be located at the AC grid connection 320. The ACdiagnostic module can comprise one or more sensors in communication withthe control software module 225. The AC diagnostic module 407 canprovide data to the control software module 225 about the flow of powerfrom the utility grid to the microgrid module and the control softwaremodule 225 can control the power flow at this connection with one ormore controllable elements in the physical circuitry layer. The AC gridinput bus also can be coupled to converter 411 for converting AC powerto DC power that flows to the DC input bus 420. The DC input busreceiving power from the AC grid input bus 409 can also comprise anotherDC diagnostic element 413.

Referring to the exemplary illustration in FIG. 4B, one can see thatconnections A, B, C, and D from FIG. 4A have corresponding connectionpoints A, B, C, and D in FIG. 4B. These connection points at A, B, C,and D do not represent physical elements of the microgrid module, butmerely illustrate the connection points between FIGS. 4A and 4B. FIGS.4C and 4D have a similar arrangement and FIGS. 4A-4D are intended toprovide a more detailed illustration of the overview of the exemplaryembodiment shown in FIG. 3.

In FIG. 4B, the DC input bus 420 has two primary connections. First, theDC input bus 420 can be coupled to a DC output bus 350 for supplying DCpower from the microgrid module. The DC input bus 420 and DC output bus350 may be linked through a power converter (not shown in FIG. 4B) ifneeded to adjust the input and output voltages. While the embodimentdescribed in connection with FIGS. 4A through 4D includes a DC input busand a DC output bus, those of skill in the art will recognize that twodistinct DC buses are not required. For example, other microgrid modulesmay comprise a single DC bus that receives DC power at one point anddelivers DC power at another point.

Second, the DC input bus can feed one or more converters 435 implementedto convert DC power to AC power for distribution on the AC output bus446. The AC output bus 446 is coupled to the AC grid input bus 409 and atransformer 440 can be placed between the AC grid input bus 409 and theAC output bus 446 if needed to adjust the input and output voltages. Asillustrated in exemplary FIG. 4B, an AC diagnostic element 430 can beplaced between converter 435 and the AC output bus 446. The ACdiagnostic element 430 can comprise one or more sensors allowing thecontrol software module 225 to monitor and control the operation of thephysical circuit layer of the microgrid module.

FIG. 4B includes connection points E and F to the elements of FIG. 4C.Exemplary FIG. 4C shows additional components of the exemplary microgridmodule including internal ultra-capacitor 442 and internal battery 444.In alternate embodiments, the internal energy storage components shownin FIG. 4C may not be internal parts of the microgrid module but may beexternal and coupled to the microgrid module. For example, as shown inFIG. 4C, the DC output bus 350 (not shown in FIG. 4C) may be coupled toan external battery via connection 446. The energy storage devices shownin FIG. 4C are coupled to the DC output bus 350 via converters 439 and448. These converters function to convert the DC voltage levelassociated with the energy storage elements with the voltage level ofthe DC output bus 350. Specifically, the voltage level associated witheach energy storage device may be substantially different from that ofthe DC bus. Moreover, the voltage levels associated with each energystorage device may vary substantially depending on the state-of-chargeof the energy storage device. In general, as an energy storage device ischarged, its associated voltage increases. Similarly, in general, as anenergy storage device is discharged while delivering energy to themicrogrid module, the associated voltage decreases. Power converters 439and 448 can adjust voltage levels so that the voltage level of the DCoutput bus 350 and the energy storage devices is consistent.

The energy storage devices also are coupled to one or more DC diagnosticelements 436, 433 and 450. As with other diagnostic elements previouslydiscussed, the DC diagnostic elements 436, 433 and 450 can comprise oneor more sensors in communication with the control software module 225.The energy storage devices illustrated in FIG. 4C are merelyrepresentative and those of skill in the art will appreciate that otherarrangements of energy storage devices can be placed either internal orexternal to the microgrid module and perform a similar function ofstoring energy provided by the microgrid module and subsequentlyproviding it back to the microgrid module as needed.

Referring to FIG. 4D, exemplary elements connected to points G and Hfrom FIG. 4B are illustrated. Point G shows the connection of the DCoutput bus 350 to a bus interface controller 455. The bus interfacecontroller 455 controls the flow of power between the microgrid moduleillustrated in FIGS. 4A-4D and one or more other microgrid modules. Asdescribed in further detail in the related patent applications filedconcurrently with this application, multiple microgrid modules can becoupled and the bus interface controller 455 manages the flow of powerbetween the coupled microgrid modules. The bus interface controller 455typically comprises control and power converter circuits thatcommunicate with a controlling software module such as the power routercontrol software module 230 illustrated in FIG. 2. One or more microgridtie connections 459 connect the DC output bus 350 to other microgridmodules. The DC output bus can also comprise one or more DC diagnosticelements 464 and 457 which can perform sensing functions as describedpreviously.

FIG. 4D also illustrates exemplary elements connected to the AC outputbus 446 at point H. One or more AC load connections 340 can be coupledto the AC output bus 446. The 3-phase AC load connection shown in FIG.4D is merely exemplary and a variety of AC loads having differentvoltages and phase combinations can be connected to the AC output bus446 of the microgrid module. The AC load connections can also compriseAC diagnostic elements similar to those described previously.

Referring to FIG. 5, an exemplary microgrid 500 is illustrated. In thisinstance, microgrid 500 is providing power to a site such as a hospital(not shown in FIG. 5) via output bus 503. The output bus 503 maytransmit either AC or DC power from the microgrid module 505 to thesite. The microgrid module 505 is coupled to the conventional utilitypower grid via AC grid input bus 512 and to various distributed energyresources. The distributed energy resources illustrated in the exemplarymicrogrid 500 in FIG. 5 include two pyrolysis generator sets 514 and 516that burn waste from waste input containers 518 and 520. The distributedenergy resources also include methane generator set 522 and solar powervia a solar power input 528. Outputs from the microgrid 500 includeuseable biofuel 524 and ash waste output 526.

The exemplary microgrid 500 includes energy storage devices 530, such asbatteries and ultra-capacitors. As explained previously, in otherembodiments of the invention different energy storage devices can beimplemented in different arrangements. For example, the energy storagedevices can be located within the microgrid module 505 or can be locatedoffsite from the microgrid module 505. The exemplary microgrid 500 shownin FIG. 5 also includes transformer 532 located in cage 534. In certainembodiments of the invention where the microgrid module is handlinglarge loads, a separate transformer outside of the microgrid module 505,such as transformer 532 shown in FIG. 5, can be beneficial. The cage 534surrounding the transformer 532 helps to insulate surrounding componentsfrom the powerful electric fields generated by the transformer 532. Inembodiments using a transformer 532, the output bus 503 is typicallyconnected to the transformer 532 instead of being connected directly tothe microgrid module 505.

Although the details of the components of the microgrid module 505 arenot labeled in FIG. 5, microgrid module 505 comprises a physicalcircuitry layer that includes AC and DC buses, power converters,sensors, and controllable elements. The microgrid module 505 alsocomprises a microgrid computer on which is installed a power managementsoftware module, a control software module, and local memory containingrules for operating the microgrid module 505. The microgrid computer cancommunicate with other computing devices via network cables (not shown)or via a wireless communications antenna 536. For example, the microgridcomputer may communicate with remote computing devices or databasescontaining business parameters used by the power management softwaremodule. The microgrid computer may also transmit sensor data or otherlog data concerning the operation of the microgrid module 505 to aremote computing device.

Those of skill in the art will recognize that the microgrid 500illustrated in FIG. 5 is merely exemplary and that other microgrids canbe designed in different arrangements within the scope of thisinvention. For example, in alternate embodiments of the invention, themicrogrid may comprise different distributed energy resources or themicrogrid may not be connected to the conventional utility power grid.Likewise, alternate embodiments of the invention may not include energystorage devices or the energy storage devices may be only internal tothe microgrid module 505. In other embodiments, the microgrid computercan be implemented in a variety of computing environments and caninclude other software such as a power router software module describedfurther in the related patent applications filed concurrently with thisapplication.

Referring to FIG. 6, an exemplary mobile microgrid 600 is illustrated.Many of the components illustrated in the mobile microgrid 600 aresimilar to those illustrated in microgrid 500 of FIG. 5, however, mobilemicrogrid 600 can be easily transported in a trailer to a variety oflocations. The mobile microgrid 600 comprises a microgrid module 605coupled to output buses 610 that transmit AC or DC power to one or moreloads. The microgrid module 605 is coupled to two distributed energyresources—a methane generator 612 and a pyrolysis set 614—via a DC inputbus (not shown). The distributed energy resources can also produceuseable bio-fuel 618 and ash waste 620.

The microgrid module 605 also is coupled to energy storage devices 616,such as batteries or ultra-capacitors or a combination of both. Theenergy storage devices 616 can be charged by power supplied to themicrogrid module 605 by the distributed energy resources 612 and 614.The energy storage devices 616 also can supply power for distribution bythe microgrid module 605 via the output bus 610 to a load. For largeloads, the microgrid module 605 can distribute power through atransformer such as transformer 622 which is shown located in aprotective cage.

The microgrid module 605 in the mobile microgrid 600 can operate in muchthe same way as the microgrid modules described previously in FIGS. 2,3, 4 and 5. For example, microgrid module 605 can comprise a physicalcircuitry layer including AC and DC buses, controllable elements,sensors, and power converters. Microgrid module 605 can also comprise amicrogrid computer installed with a power management software module, acontrol software module, a local memory containing rules for operatingthe microgrid module. The microgrid computer can also communicate withremote computing devices via communications antenna 624. For example,the microgrid computer can receive parameters governing the operation ofthe mobile microgrid 600 via the antenna 624. The microgrid computer canalso transmit data concerning the operation of the mobile microgrid 600to a remote computer.

Those of skill in the art will appreciate that the mobile microgrid 600illustrated in FIG. 6 is merely exemplary and that alternate embodimentscan comprise different arrangements of components. In alternateembodiments of the mobile microgrid, different distributed energyresources can be employed. Similarly, alternate embodiments of themobile microgrid may not require an external transformer such astransformer 622 or may not include energy storage devices such asdevices 616.

Referring to FIG. 7, a method 700 is illustrated describing theoperation of a microgrid module with a power management software modulein accordance with one exemplary embodiment of the invention. Exemplaryprocess 700 begins with the power management software module 228receiving a business parameter from a remote computer-readable storagedevice 238 in step 705. For example, the business parameter may indicatea preference for power from a renewable energy source such wind orsolar. While the business parameter is stored in remotecomputer-readable storage device 238 in the preferred embodiment, inother embodiments the business parameter can be stored in otherlocations including in local data storage device 235. In step 710, thepower management software module 228 converts the business parameterinto one or more rules to control the operation of the microgrid module.For example, the business parameter indicating a preference for powerfrom a renewable energy source can be translated into rules identifyingcertain renewable distributed energy resources coupled to the microgridmodule as the preferred sources of power over other sources of powercoupled to the microgrid module.

Turning to step 715, the control software module 225 can receive datafrom a sensor 210 concerning a power interruption in the power suppliedto the microgrid module. While step 715 and the other steps illustratedin exemplary process 700 are shown in sequence, those skilled in the artwill appreciate that certain steps can occur in parallel or in adifferent sequence from that illustrated in process 700. For example,the receipt of data from sensors at the control software module in step715 is a step that can occur at various times throughout process 700. Instep 720, the control software module 225 can retrieve one or more rulesfrom the local data storage device 235 and apply those rules to the datareceived from sensor 210. In step 725, the control software module 225selects a command based on the rules. Using the previous example of arule indicating a preference for renewable power sources, the commandthe control software module sends to a controllable element 215 may beto begin drawing power from a different renewable power source. In step725, the control software module 225 also stores the data received fromthe sensor 210 in a data storage device such as device 238. The sensordata is stored so that it can be available for later use by the powermanagement software module 230 to adjust rules based on the operation ofthe microgrid module.

Turning to step 730, control software module 225 sends a command to acontrollable element 215 to initiate power delivery on the AC grid inputbus 409. A power converter 411 can convert the AC power received on theAC grid input bus 409 to DC power for delivery on the DC output bus 350in step 735. Alternatively, the converted DC power can be used to chargestorage devices 442 and 444. In step 740, the power management softwaremodule 228 retrieves sensor data stored in remote memory device 238 inorder to evaluate the operation of the microgrid module. If appropriate,in step 745 the power management software module 228 can modify the rulestored in local memory 235 after evaluating the sensor data. Forexample, a collection of sensor data may indicate that a particularrenewable power source will not be available for an extended time. Insuch a situation, the power management software module 228 can modifythe rules stored in local memory 235 so that the microgrid module doesnot attempt to draw power from the renewable power source while it isunavailable. Finally, in step 750, the power management software module228 can store the modified rule in local memory 235 for use by thecontrol software module 225.

The steps in exemplary process 700 are merely one example of theapplications for the power management software module and the microgridmodule. Those of skill in the art will appreciate that not all of thesteps illustrated in process 700 are required in order to use themicrogrid module. Furthermore, the steps of process 700 can be performedin other sequences and other steps can be added for other applicationsof the microgrid module.

In conclusion, the invention, as described in the foregoing exemplaryembodiments, comprises a microgrid module that can receive either AC orDC power from a variety of power sources and supply either AC or DCpower to a load or storage device. The microgrid module comprises apower management software module that can access business parameters andconvert those business parameters into rules that control the operationof the microgrid module. A control software module has access to therules stored locally on a microgrid computer. The rules determine whatactions the control software module takes in response to changes in thepower available to the microgrid.

The embodiments set forth herein are intended to be exemplary. From thedescription of the exemplary embodiments, equivalents of the elementsshown herein and ways of constructing other embodiments of the inventionwill be apparent to practitioners of the art. For example, conventionalelectrical components can be added or modified within the microgrid butremain within the scope of the invention. Similarly, the methodsdescribed herein are merely exemplary and the control software modulecan be designed in a variety of ways to control the operation of themicrogrid module. Many other modifications, features and embodiments ofthe invention will become evident to those of skill in the art. Itshould be appreciated, therefore, that many aspects of the inventionwere described above by way of example only and are not intended asrequired or essential elements of the invention unless explicitly statedotherwise. Accordingly, it should be understood that the foregoingrelates only to certain embodiments of the invention and that numerouschanges can be made therein without departing from the spirit and scopeof the invention.

1. An apparatus for managing a microgrid module comprising: a microgridcomputer comprising a power management software module processing abusiness parameter; a local computer readable storage device storing arule created by the power management software module from the businessparameter; a control software module using the rule stored in thecomputer readable storage device to send a command to a firstcontrollable element to control the operation of the microgrid module; acircuit layer comprising an AC input bus coupled to an AC output bus anda first converter; a DC bus coupled to a second converter; the firstconverter coupled to the DC bus; the second converter coupled to the ACoutput bus; a first sensor coupled to the DC bus, the sensor sendingdata to the control software module; and the first controllable elementcoupled to the AC input bus, the first controllable element receivingthe command from the control software module.
 2. The apparatus of claim1, wherein the control software module stores the data from the sensorin a remote computer readable storage device.
 3. The apparatus of claim2, wherein the power management software module retrieves the data fromthe sensor stored in the remote computer readable storage device;modifies the rule based on the data; and stores the modified rule in thelocal computer readable storage device.
 4. The apparatus of claim 1,wherein the DC bus is coupled to one or more of a solar energy source, awind energy source, a biofuel energy source, and a power storage device.5. The apparatus of claim 1, wherein the AC input bus is coupled to autility AC power grid.
 6. The apparatus of claim 1, wherein the AC inputbus is coupled to one or more of a solar energy source, a wind energysource, a biofuel energy source, and a power storage device.
 7. Theapparatus of claim 1, wherein the AC input bus is coupled to atransformer.